Electric-arc-welding system.



F. THORNTON, JR. & E. S. ZUCK.

ELECTRIC ARC wsinms SYSTEM.

APPLICATION FILED APR.'I. 1915.

Pat ented Mar. 4,1919.

LQQGQZO.

, 'INVENTOR I Fran/r mar/7 20/1 J/r 8t Emerson 3. Zuc K ATTORNEY WITNESSES PATENT FRANK THORNTON, JR., F PITTSBURGH, AND EMERSON S. ZUCK, 0F WILKINSBURG,

IGNORS comm, A conronnrron T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING OF. PENNSYLVANIA.

nnncrnIc-Anc-wnmmc srs'rnn.

To all whom'z't may concern:

Be it known that we, FRANK Tnonn'ron, Jr., a citizen of the United States, and a resident of- Pittsburgh, in the county of Allegheny and Stateof Pennsylvania, and EMERSON S. ZUCK, a citizenof the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electric-Arc-Welding Sys tems, of which the following is a specification.

Our invention relates to electricarc weldin systems,vand it has for its object to provide an arc welding system which shall be simple in arrangement and efiicient in operation and which shall be provided -with means for automatically adjusting the circuit conditions without attention on the'part of the operator.

The single figure of the accompanying drawing is a diagrammatic view showing a welding system constructed in accordance with our invention.

In electric arc welding, it often happens that the working electrodes, especially metal electrodes, become fused or frozen to the work, resulting in a dead short circuit and a rush of current that is limited only by the resistance of the weldingvcircuitf In order to restrain such rushes of current, a resistance element is somet' es placed permanently in series with the arc circuit in addition to the usual steadying resistors required by the arc, Such extra resistance elements are expens ve and consume a great deal of power.

According to our present invention, we provide meansfor interrupting the welding circuit when the currentbecomes excessive by reason of the working electrode being maintained in contact with 0r'frozen to the work, and we further provide automatic means for reestablishing the circuit and restoring it to operating condition after the electrodes have been separated andthe short circuit consequently removed. By these combined means, the electrical condition of the circuit is automatically regulated without any attention on the part ofthe operator, and dangerous current rushes are effectually prevented.

In the system shown in the accompanying drawing, a welding electrode 1 is shown in Specification of Letters Patent.

coil 20 that is insert in the normal operation of Patented-Mar. d, TQM.

. Application filed April 1', 1915. Serial No. 18,504.

cooperative relation to a metallic object 2 which diagrammatically represents the work to be welded. The electrode 1 receives current from any suitable source through a con-' ductor 3, and the work 2 is connected to the source of power through a conductor 4.. A set of steadying resistors 5 is inserted in, serise in the conductor 3. The parts thus far described constitute an ordinary arc-welding circuit.

carried by the core of a magnet switch 8. A

' resistor 9 is connected to the conductor 3 at points 10 and 11 and is adapted to be inserted in series in the conductor 3 when the conductor is interrupted at 6.

he magnet switch 8 is operated by means of a solenoid core 12 energized by a conductor 13, which is connected to the conductor 3 at a point 14 and is interrupted at 15, the terminals 16 and 17 at this point being normally connected by a bridge piece 18 that is earned by the core of an overload relay 19. The relay core 19 is o erated by means of a es in seriesin the conductor 3.

The core of the magnet switch 8 carries, in

.addition to the bridge piece 7, a second bridge piece 21 that is adapted to connect terminals 22 and 23 connected respectively to conductors 24 and 2.5. The conductor 24 is joined to the conductor 4 at the point 26-, and the conductor is joined at 27 to a conductor 28 that is connected to the solenoid coil 12 of the magnet switch. A shunt circuitaround the terminals 22 and 23 is provided by the conductor 28 and. a conductor 29, terminals 30 and 31 of the conductors 28 and 29', res ectively, being adapted to be connected by the bridging piece 32 of a relay 33 that is energized by means of a solenoid coil 34- the ends of which are connected to the conductors 3 and 1 at the points 35 and 36, respectively.

The overload relay 19 is so designed that,

cuit, the bridge iece 18 will connect the terminals 16 and 1 and current will therefore flow through the conductor 13 and the coil 12 to maintain the magnet switch 8 in position to close the conductor-'3 at, 6. In this position of the magnet switch 8, the bridge the welding cirpiece 21 connects the terminals 22 and 23, and the current from the coil 12 therefore flows to the conductor 4 through conductors 25 and 24.

If the welding electrode should become frozen to the work, the resulting rush of current will raise the core 19 of the overload relay which, in turn, opens the main circuit at 6, since the core of the magnetic switch 8 drops by gravity and remains in its lower position, as shown, as long as its coils are denergized. The resistance element 9 is inserted in the main circuit by the foregoing operation of the magnet switch 8, and the resistance of this element should be great enough to prevent current flow in the main circuit almost entirely. Since the overload no longer exists, the relay 19 is again closed by gravity, but the circuit which energizes the magnet switch 8 remains open, since the bridge pieces 21 and 32 are both in their lower positions, as shown, the bridge piece 21 having been carried down by the opening of the magnetic switch 8, while the relay 33 is inoperative since the small current flowing in the main circuit is shunted around it through the electrodes 1 and 2. When the electrode 1 is broken away from the work 2, a relatively high voltage is impressed upon the coil 34: of the relay 33, and the current flowing through this coil raises the relay core and connects the terminals 30 and 31. This operation closes the auxiliary circuit which includes the operating coils of the magnet switch 8, thus raising the switch core and closing the main circuit at 6. The welding circuit is now in its normal operating condition, strike the welding are without operating switches or giving'the circuit any-other attention.

It will be evident from the foregoing description, and from the drawing, that our welding system effectually prevents dangerous surges of current that tend to result from the freezing of the welding electrode to the work, and that the removal of the electrode from the work accomplishes the renergizing of the circuit. Positive current regulation is thereby assured, and much time is saved which would otherwise be consumed in making circuit adjustments. The circuits and apparatus which we have shown and described ma be variously modified within the scope 0 our invention, and it is therefore to be understood that no limitations are to be imposed upon our invention except such as are indicated in the appended claims.

We claimas our invention: a

1. An arc welding system comprising welding electrodes, a welding circuit including the said electrodes, means for partially deenergizing the said circuit when the said electrodes are brought into contact, and

and the operator may againother means for automatically renergizing the said circuit after the said electrodes are separated.

2. An arc welding system comprising welding electrodes, a circuit adapted to supply energy to thesaid electrodes, means for partially denergizing the said circuit when the said electrodes are maintained in contact for a substantial period, and other means, operated by the residual currentin the said circuit, for automatically reenergizing the said circuit after the said electrodes are separated.

3. An arc welding system comprising welding-electrodes, a circuit adapted to supply energy to the said electrodes, a magnetically-operated switch adapted to control the said circuit, an overload relay in the said circuit adapted to operate the said switch when the current in the said circuit exceeds a predetermined value, and'means for operating the said switch to restore the said circuit to its normal condition when the said electrodes are separated.

1. An arc welding system comprising welding electrodes, a circuit adapted to supply energy to the said electrodes, a resistance element, means for normally shunting the current in the said circuit around the said resistance element and for inserting the said resistance element in series in the said circuit when the said electrodes are maintained in contact for a substantial period, and additional electro-responsive means for restoring the circuit to its normal condition when the said electrodes are separated.

5. An arc welding system comprising welding electrodes, a main circuit adapted to supply energy to the said electrodes, a magnetically operated switch adapted to control the said circuit, an auxiliary circuit for enegizing the said magnetically operated switch, an overload relay adapted toopen the said auxiliary circuit when the said electrodes are maintained in contact for a substantial period, and means for closing the said auxiliary circuit when the said electrodes are separated.

6. An arc welding system comprising welding electrodes, a main circuit adapted to supply energy to the said electrodes, a magnetically-operated switch adapted to control the said circuit, an auxiliary circuit for energizing the said magnetically operated switch, an overload relay adapted to open the" said auxiliary clrcuit when the said electrodes are maintained in contact for a substantial period, and a second relay adapted to be energized when the said electrodes are separated and to thereby close the said auxiliary circuit.

' 7. An arc welding system comprising welding electrodesfa main circuit adapted to supply energy to the said electrodes, a resistance element, a magnetically opera mecpao I said resistance element, and also adapted,

when denergized, to put the said resistance element in series with the said main circuit,

an auxiliary circuit for energizing the said magnetically-operated switch, an overload relay adapted to 0 en the said auxiliary circuit whenthe sai welding electrodes are 10 maintained in contact for a substantial period, means for maintaining the saidauxlliai'y circuit open as long as the said elec trodes are in contact, and electro-responsive means for closing the said auxiliary circuit when the said electrodes are separated.

In testimony whereof we have hereunto subscribed our names this 29th day of March, 1915. t

' FRANK THORNTON, JR;

EMERSON S. ZUCK. 

